1. Field of the Invention
The present invention relates to a protection cap for protecting a ferrule mounted in an optical connector or a hybrid connector having an optical connector portion.
2. Related Art
In various types of vehicles such as an automobile, there are provided an extremely large number of control signals. When each control signal is transmitted through an individual signal path line, a large number of signal path lines are required, so that a wiring harness thereof undesirably becomes heavy. Furthermore, various types of recent electronic instruments require transmitting information having a larger capacity and a higher density, also resulted in a heavy weight wiring harness thereof. Therefore, a recent wiring harness partially includes optical fiber cables (or optical fiber cords), for example, for connection between nodes of the wiring harness.
A system including such a wiring harness requires an optical connector or a hybrid connector each having a ferrule surrounding an optical cable. The ferrule has an end face at which the optical cables are exposed. Note that the hybrid connector integrally has an electrical connection portion and an optical connection portion.
The optical connector or the hybrid connector is directly protected by a protection cap until the use of the connector to protect the ferrule having the end face at which the optical cable is exposed.
Referring to FIG. 5, such a protection cap will be briefly discussed hereinafter. A protection cap 1 is made of a synthetic resin material and is defined in a rectangular box-shape. The protection cap has an entrance opening 2 from which an optical connector (not shown) is inserted. Furthermore, the protection cap has a locked portion 3 engaged with a lock projection of the optical connector.
Note that the protection cap 1 of FIG. 1 can be molded by molding dies which can be removed in a direction parallel to an arrow P (double-headed) after the molding. For an easy removal of the molding dies, the protection cap has an end wall 5 having a cutout edge so that the locked portion 3 has a large opening.
However, thus defined protection cap 1 has the following disadvantage, because the protection cap 1 needs to have the locked portion 3 engaged with the lock projection of the optical connector to prevent an unintentional disengagement of the protection cap from the optical connector. That is, the locked portion 3 has the large opening due to the use of the simplified molding dies. From the large opening, undesirable dust or contaminants may enter into the protection cap. Thus, the protection cap 1 is insufficient for protecting the optical connector.
Therefore, as illustrated in FIG. 6, a protection cap 7 having a minimum opening 6 would be proposed. However, the protection cap 7 requires complicated molding dies, one of which needs to slide in a direction parallel to an arrow Q. This increases a production cost of the protection cap 7, so that the protection cap 7 would be commercially unsuccessful.
In view of the above-mentioned problem, an object of the invention is to provide a protection cap which can surely protect a ferrule of an optical connector. Furthermore, the protection cap can be produced without an expensive cost.
For achieving the object, a protection cap according to the present invention is removably attached to an optical connector or a hybrid connector each having a cable ferrule therein, the cable ferrule having an end face at which an optical cable core is exposed. The protection cap has a locked portion engaged with a lock portion of the optical connector or the hybrid connector and has a projection on an inner wall of the protection cap for protectively covering the end face of the cable ferrule. The protection cap is of a box shape which can be molded by one or more molding dies that can be removed parallel to an engagement direction of the protection cap with the connector.
The protection cap is defined by the molding dies that can be removed parallel to the engagement direction of the protection cap. Thus, the molding dies are simplified to be advantageous for molding the protection cap. Although the protection cap has the lock portion with a large opening due to the simplified molding dies, the protection cap can surely protect the ferrule by the projection formed on the inner wall of the protection cap.
Preferably, the projection has an annular tapered edge at a tip of the projection.
The tapered edge formed in the projection can intimately contact the ferrule, so that an exposed core of the ferrule is protected from dust.
Preferably, the projection can be inserted into an accommodation chamber of the cable ferrule of the connector until a tip end surface of the connector abuts against the inner wall of the protection cap, when the protection cap receives the connector. Thereby, the protection cap can further surely protect the ferrule by the projection and the inner wall of the protection cap.